1. Field of the Invention
The present invention relates to supercooled water-freezing method and apparatus which are used in an ice thermal storage system of a freezing machine, for example and adapted to release the supercooled water from a supercooled state through freezing. The invention also relates to a method and a system for circulating or flowing cooled water at least a part of which is released from a supercooled state. Particularly, the invention relates to the method and the apparatus for freezing supercooled water having a low supercooled degree, which method and apparatus can positively release the supercooled water from the supercooled state at an arbitrary point of time and at an arbitrary place. The invention also relates to the method and the system for circulating or flowing the supercooled water at least a part of which is released from the supercooled state.
2. Related Art Statement
A method in which flowing supercooled water is made to spontaneously fall and impinge upon a plate to freeze it is known as a conventional supercooled state-removing (freezing) technique.
However, since this method requires a sufficient long distance for freezing, an apparatus for this becomes bulky. Further, the supercooled water cannot be frozen at any time or any place. In addition, if the supercooled water is at a low supercooled degree, it is unfavorably difficult to freeze the water.
The present invention is aimed at solving the problems of the prior art apparatuses through discovery of the new supercooled state-removing method and apparatus having a smaller size than the conventional ones and being able to positively release the supercooled water from the supercooled state at any time and any place and rapidly freeze the supercooled water, even if the supercooled water is at such a low supercooled degree as not allowing easy freezing.
A first aspect of the present invention relates to a method for freezing supercooled water comprising the steps of (1-1) filling said supercooled water in a sealed container, reducing pressure of said supercooled water to generate bubbles from the supercooled water, mixing said generated bubbles in the supercooled water, or (1-2) filling said supercooled water in a sealed container with a bubble-mixing inlet, reducing pressure of the supercooled water to mix bubbles into the supercooled water from outside of the container through the bubble mixing inlet, or (1-3) filling said supercooled water in the sealed container with the bubble-mixing inlet, introducing bubbles into the supercooled water from outside the container through the bubble-mixing inlet under pressure, mixing the bubbles into the supercooled water, (2) simultaneously repeating expansion, compression, disruption, clustering and disappearance of the bubbles mixed into the supercooled water and (3) thereby freezing the supercooled water by vigorously oscillating gas-liquid boundaries between the bubbles and the supercooled water.
A second aspect of the present invention relates to an apparatus for producing frozen water from supercooled water, comprising (a) a sealed container with a supercooled water-filling opening or a sealed container with a supercooled water-filling opening and a bubble-mixing inlet for sealingly filling said supercooled water therein, (b) a charger for filling the supercooled water into the sealed container, (c) a bubble mixer for mixing bubbles into the supercooled water filled in the sealed container by (c-1) reducing pressure of said supercooled water inside the container to generate bubbles from the supercooled water and mixing said generated bubbles in the supercooled water, or (c-2) reducing pressure of the supercooled water filled in said container with the bubble-mixing inlet to mix bubbles into the supercooled water from outside of the container through the bubble mixing inlet, or (c-3) introducing bubbles into the supercooled water filled in the container from outside the container through the bubble-mixing inlet under pressure to mix the bubbles into the supercooled water, wherein while the bubble mixer mixes the bubbles into the supercooled water, expansion, compression, disruption, clustering and disappearance of the bubbles are simultaneously repeated, and gas-liquid boundaries between the bubbles and the supercooled water are vigorously oscillated to produce the frozen water from the supercooled water.
In the second aspect of the present invention, it is preferable that said sealed supercooled water container is a supercooled water cylinder, said supercooled water charger is a supercooled water piston gas-tightly, liquid-tightly and slidably fitted into the supercooled water cylinder, said supercooled water piston also serves as the bubble mixer, and the bubbles are mixed into the supercooled water inside the sealed supercooled water container by reducing pressure of the supercooled water through operating the supercooled water piston.
Further, in the second aspect of the present invention, it is preferable that said bubble mixer comprises a gas cylinder and a gas piston gas-tightly and slidably fitted into said gas cylinder, the gas cylinder and the sealed supercooled water container are connected to each other through the bubble-mixing inlet, the bubbles are introduced into the supercooled water in said container under pressure through the bubble-mixing inlet by operating the gas piston.
A third aspect of the present invention relates to a method for circulating or flowing supercooled water, comprising the steps of (1-1) taking at least a part of circulating or flowing supercooled water into a sealed container with a supercooled water-filling opening, reducing pressure of said supercooled water filled in the container to generate bubbles from the supercooled water, mixing said generated bubbles in the supercooled water, or (1-2) taking at least a part of circulating or flowing supercooled water into a sealed container with a supercooled water-filling opening and a bubble-mixing inlet, reducing pressure of the supercooled water filled in the container to mix bubbles into the supercooled water from outside of the container through the bubble mixing inlet, or (1-3) taking at least a part of circulating or flowing supercooled water into a sealed container with a supercooled water-filling opening and a bubble-mixing inlet, introducing bubbles from outside the container through the bubble-mixing inlet under pressure to mix the bubbles into the supercooled water, (2) simultaneously repeating expansion, compression, disruption, clustering and disappearance of the bubbles mixed into the supercooled water, (3) thereby freezing the supercooled water by vigorously oscillating gas-liquid boundaries between the bubbles and the supercooled water, and (4) returning the supercooled water at least a part of which is released from being supercooled into the circulating or flowing supercooled water.
A fourth aspect of the present invention relates to a supercooled water-circulating or flowing system, comprising (a) means for circulating or flowing supercooled water, (b) a sealed container provided with a supercooled water-filling opening or a sealed container provided with a supercooled water-filling opening and a bubble-mixing inlet, said container being adapted for sealingly receiving the supercooled water, (c) a charger for filling at least a part of the circulating or flowing supercooled water into the sealed container, (d) a bubble mixer for mixing bubbles into the supercooled water in the sealed container by (d-1) reducing pressure of said supercooled water filled in the container to generate bubbles from the supercooled water, and mixing said generated bubbles in the supercooled water, or (d-2) reducing pressure of the supercooled water filled in the container to mix bubbles into the supercooled water from outside of the container through the bubble-mixing inlet, or (d-3) introducing bubbles into the supercooled water filled in the container from outside the container through the bubble-mixing inlet under pressure to mix the bubbles into the supercooled water, wherein while the bubble mixer mixes the bubbles into the supercooled water, expansion, compression, disruption, clustering and disappearance of the bubbles are simultaneously repeated, gas-liquid boundaries between the bubbles and the supercooled water are vigorously oscillated to produce frozen water from the supercooled water, and a part of the frozen supercooled water is returned to the circulating or flowing supercooled water.
According to the present invention, while (1-1) said supercooled water is filled in a sealed container, pressure of said supercooled water is reduced to generate bubbles from the supercooled water, said generated bubbles are mixed in the supercooled water, or (1-2) said supercooled water is filled in a sealed container with a bubble-mixing inlet, pressure of the supercooled water is reduced to mix bubbles into the supercooled water from outside of the container through the bubble mixing inlet, or (1-3) said supercooled water is filled in the sealed container with the bubble-mixing inlet, bubbles are introduced into the supercooled water filled in the container from outside the container through the bubble-mixing inlet under pressure, the bubbles are mixed into the supercooled water, (2) simultaneously expansion, compression, disruption, clustering and disappearance of the bubbles mixed into the supercooled water are repeated and (3) thereby a part of the supercooled water is frozen and ice nuclei are formed by vigorously oscillating gas-liquid boundaries between the bubbles and the supercooled water. Consequently, the supercooled water can be frozen in the sealed container. When the water which is released from the supercooled state is discharged into the supercooled water outside the container, water in the surrounding area can be continuously frozen. The supercooled water inside the container is converted to a sherbet-like state after being released from the supercooled state.
Therefore, according to the freezing apparatus of the present invention, the supercooled water at such a low supercooled state as not allowing easy freezing can be instantly frozen at any time through positively eliminating the supercooled state with the smaller apparatus as compared with the prior art. In addition, since a number of such downsized apparatuses can be easily installed in the supercooled water or moved therein, the supercooled water can be frozen at any place.
Therefore, when the freezing apparatus according to the present invention is used as a supercooled state-eliminating apparatus for an ice thermal storage system, for example, the freezing load of the freezer can be largely reduced, which can greatly contribute to the energy storage field, the freezing air conditioning field and the environmental field.
In the present invention, since the sealed container is provided with the supercooled water inlet and the supercooled water outlet which can be opened and closed, the supercooled water inlet and the bubble-mixing inlet and the water outlet are controlled to be opened or closed in connection with the steps of filling the supercooled water into the container and the expansion, compression, disruption, clustering and disappearance of the bubbles, the supercooled water can be continuously frozen and discharged. In this case, one opening may be commonly used for two kinds of the supercooled water inlet and the supercooled water outlet. As the mixer for mixing the bubbles into the supercooled water in the container from outside of the container, means for reducing pressure in the container is used. For example, the sealed supercooled water container is a supercooled water cylinder, said supercooled water charger is a supercooled water piston gas-tightly, liquid-tightly and slidably fitted into the supercooled water cylinder, said supercooled water piston also serves as the bubble mixer, and the bubbles are mixed into the supercooled water inside the sealed supercooled water container by reducing pressure of the supercooled water through operating the supercooled water piston.
Further, said bubble mixer comprises a gas cylinder and a gas piston gas-tightly and slidably fitted into said gas cylinder, the gas cylinder and the sealed supercooled water container are connected to each other through the gas-mixing inlet, and the bubbles are introduced into the supercooled water in said container under pressure through the bubble-mixing inlet by operating the gas piston. Alternatively, a gas-feeding pump is provided as the gas mixer, so that the bubbles can be mixed into the supercooled water inside the supercooled water container through the bubble-mixing inlet by operating the gas feeding pump.
Furthermore, according to the present invention, a heater may be provided around the supercooled water-receiving container. According to such a freezing apparatus, when the cylinder is heated with the heater as the water released from the supercooled state through mixing between the bubbles and the water is discharged outside the cylinder, attachment of ice nuclei upon the inner wall of the cylinder can be prevented without excess heating of the supercooled water around the cylinder. This can facilitate the continuous use of the apparatus.